A new theory of time; Events and observability; Multimedial units and language: verbal and nonverbal communication; Judgment formation and problems of description; Memory and perception: some new models; Stochastic models of expertise formation, opinion change, and learning.

The aim of this note is to analyze the problems connected with con- straints on descriptions imposed by limitations of knowledge and/or observability, and constraints imposed by the language used.

Postulates concerning subjective time perception are formulated, which imply the existence of two interval time scales, objective and subjective, allowing to study various types and magnitudes of distortion of time per- ception.

The purpose of this note is to analyze the structure of concepts, treated as fuzzy subsets of a certain set. The concepts are assumed to be composed out of more elementary ones. Such an approach was developed mainly to get an empirical access to the values of membership functions of concepts.